I don't know the products but if they are reasonably new versions they have probably been written with USB in mind. Presumably the software assumes the CNC device has a USB connection?

Not really. A parallel port interface is much more common and/or would be the standard for Mach 3 or Linux CNC. You can find USB interfaces but they are pretty expensive (compared to a parallel port interface card you could throw in a slot in your computer), will have a dedicated microcontroller translating the protocol used, and requires the software to support that proprietary interface.

With a parallel port the 17 pins (8 pins of a parallel port are GND only) are treated like a general purpose IO; the software will typically let you assign the pins any way you like, and 17 pins is plenty for three step/dir stepper interfaces, a spindle drive, limit switches, E-stop, etc. Parallel port "breakout" boards are just a bunch of handy connectors and optical isolators.